I haven't worked with midi for about 15 years. But, this is what I remember.

Master and slave refers to the clock source. If you want the sound module to create sounds using the KN7000 as the "note" source, you need to do as Bill says by connecting the midi out of the KN7000 to midi in of the sound module. You need to decide what notes of the KN7000 you want to use to make the sound module "sound". Then set that note source (probably Right Hand) to the midi channel that you choose to use. Then be sure the Hammond is set to receive on that same channel. I would use the KN7000 as the clock source so it would be considered the master.

What you do with the output of the sound module is a matter of choice. I assume the output is audio, not midi. So the audio out of the module would go to your amplifier input. That could be the aux input of the KN7000.